3D-Printed frequency-scanned slot array in grating waveguide

Abstract

In this work, a linearly-polarized frequency-scanned slot-antenna linear array fed by a travelling wave in grating waveguide is designed at 17 GHz. Additionally, the insertion of periodic gratings in the bottom broad-wall of the feeding waveguide reduces the guided wavelength of the fundamental propagating mode. Therefore, steering angles around broadside can be attained in the radiation pattern, contrary to conventional travelling-wave designs where grating lobes would inevitably appear. Furthermore, tuning posts are included in the radiating element design to mitigate the mismatch provoked by uniform phase feeding. A 16-element array is fabricated to validate the design, which experimentally shows a continuous angular scanning range of ±10°around broadside in the band from 16 to 18 GHz, with a peak gain of 18 dBi and a maximum gain drop of 4 dB